By Jennifer Silver, JMMDS
Here in northern New England, the snow is finally receding and spring bulbs are poking up—but look before you leap! Your soil may not be ready. Here’s how to tell if it’s safe to get to work in the garden.
If you give your garden soil the squeeze-and-toss test and it holds its shape like the clump on the left, it’s still too wet to work. The handful on the right fell apart–a sign that it has dried out enough so that you can dig in. Photos by Jennifer Silver.
Dig down a few inches and scoop up a handful of soil. Gently squeeze it into a ball, toss it into the air, and catch it. If it holds its shape, it’s too wet to work. If it crumbles apart, you have a green light to get planting!
Why is it so important to wait until your soil passes the workability test?
I saw a bumper sticker lately that said, “Dirt Farmer.” All gardeners should aspire to be good dirt farmers. If we don’t take care of our soil, nothing will thrive in it for long. Healthy soil equals healthy plants.
If you work the soil too early, you squeeze out the air spaces between molecules. The result will be a hard, compacted surface layer. Water will not penetrate and be absorbed as readily, weeds will be harder to pull, and your plants’ roots will be gasping for air.
Diagram of soil layers, or horizons, courtesy of Spark Notes.
A very brief primer on healthy soil structure
There are three main layers (also called “horizons”) in most soil. Each layer has sub-layers, but I’ll limit this description to the principal layers.
Top layer: Approximately the top eight inches of soil are surface matter and topsoil. This is where the biological activity is going on. It should be full of humus (partially decomposed organic matter) and living organisms, including beetles, earthworms, and breathtakingly complex networks of beneficial fungi (mycorrhizae).
Subsoil: This is where clay and leached iron, aluminum, and organic compounds accumulate. There is considerably less humus. This layer stores water and nutrients and regulates the soil temperature. It also provides the air supply for deeper plant roots.
Parent material: The third layer is made up of partially broken down mineral matter. This layer helps determine the texture, acidity, and fertility of the soil (although you can also affect these factors with soil amendments). Under the parent material lies impenetrable bedrock.
Your topsoil is an ecosystem teeming with beneficial organisms. L: Earthworm. Photo: Glogster. C: Ground beetle. Photo by Jeff Hahn, courtesy of University of Minnesota Extension. R: Myccorhizae. Photo: Mushroom Research Centre.
To till or not to till?
I used to till my garden each spring, until I learned from the Master Gardener course that I was wreaking unspeakable violence on my soil structure and its living organisms. If you’re a regular reader here, you know that I now just mulch the heck out of everything instead, which adds lots of organic matter and improves the soil’s structure, health, and ability to hold water. Instead of tilling your soil, it is best to pile organic matter on top of it and plant into that added layer. The resulting biological activity will gradually improve the soil below it, while plants’ roots will penetrate and break up poor soil and bring nutrients toward the surface.
If you plant a cover crop, you’ll need to turn those plants back into the soil, but it’s not necessary to till, which churns up the soil layers much more deeply than necessary. I fork up the plants, leave them to dry on the surface for a few days, then gently turn them under and wait another day or two before planting. It’s easy to do this without disturbing more than a few inches of soil.
If you absolutely must till, be aware that it takes several years for the soil to regain its healthy composition and ecology.
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